A Correlation between the Different Models of Resistivity Sounding Data to Discover a New Fresh Water Field in El Sadat City, Western Desert of Egypt

Abstract

El Sadat City is a new urban community established in the Western Desert of Egypt near the Nile Delta. The district of the city and vicinity is covered by a thick Pleistocene section of sand and gravel facies based by a thick Pliocene layer of plastic clays.

An area, selected from the previous hydrological studies, was covered by 27 deep electric soundings in order to locate the fresh water aquifers that may occur and to identify the probable geometry of these aquifers. Data collection, reduction and analysis were achieved in site using field computers to produce the equivalent layering model and the n-layers model of each sounding. The models were used to construct the subsurface true resistivity bar sections as well as the resistivity contour sections along three profiles using the set of soundings located on each profile. Besides, subsurface horizontal contour sections were produced at different depths.

The interpretations of the analysed data revealed that most of the Pleistocene sediments act as a fresh water aquifer which is charged from the water circulated from the Delta. It was also possible to distinguish subsurface gravel rich channels which yield most of the groundwater potential in the area. The depth to fresh groundwater ranges from 35 m to 65 m according to the relative topography of each sounding site. In addition, the study indicated that another saline aquifer, of probably fossil water, occurs at greater depths beneath the fresh water aquifer. The two aquifers are vertically separated by a thick layer of impervious formations. Recommendations for drilling, in some selected sites, were reached from the present study. The subsequent drilling operations resulted in the construction of a number of heavy duty water wells (water field B with capacity of 70,000 m³/day) which satisfy the water demand of the city.